1. Field of the Invention
The present invention relates to a recording apparatus and recording method, and particularly, as in the case of facsimile equipment, to a recording apparatus and recording method in which a recording cycle is different line by line, recording is made intermittently, and a recording mode with a plurality of line densities is involved.
2. Related Background Art
In a conventional thermal recording apparatus involving a plurality of line densities of feed for recording, the same data is repeatedly recorded with the same energy applied to a thermal head for recording at a low line density. In other words, many models of current facsimile equipment have line densities of feed of 3.85 lines/mm for standard mode, 7.7 lines/mm for fine mode, and 15.4 lines/mm for super fine mode. In such a case, the length of a heating element of the thermal head is designed to be 1/15.4 mm in the direction of feed; in the super fine mode, one line is recorded in one recording operation; in the fine mode, the same data is continuously recorded twice for recording one line at a line density corresponding to the fine mode; and in the standard mode, the same data is recorded continuously four times for recording one line at a line density corresponding to the standard mode. In addition, recording paper is conveyed by 1/15.4 mm in the direction of feed at each of these recordings. Here, if lines are different, corresponding line data are different from each other.
However, in the example of prior art described above, in the standard mode and fine mode, the same data is recorded a plurality of times with the same energy applied to the thermal head at each line recording; consequently, as the count of recording increases, applied energy becomes excessive due to heat accumulation in the thermal head, causing problems of a dragged recorded image and a defaced dot. Also, if energy applied to the thermal head is reduced to prevent such dragging and defacing, there are problems of insufficient density of a recording starting line and scratches. In this connection, it is conceivable to reduce energy applied to the thermal head by a predetermined amount at each line recording when the same line data is recorded a plurality of times for recording one line at a line density corresponding to each mode. In this case, however, the state of the dragging and defacing of an image varies depending on a recording time interval from a preceding line at each line recording, and consequently the effect of reducing energy line by line is not sufficiently attained. On the other hand, it is also conceivable to detect the temperature of the thermal head and control the applied energy on the basis of the detected temperature. However, it is difficult to make a complete correspondence between an actual thermal head temperature and a thermistor temperature, and therefore the aforementioned problems cannot be solved by this method alone.
In conventional thermal recording using a full-line type thermal head, heating elements of the thermal head are divided into a plurality of blocks and are energized for recording each line, thereby dispersing electric power at recording for implementing a compact power supply. In recording with these blocks, each block is energized only once for recording (FIG. 5) or the timing of moving a recording medium such as recording paper and, the timing of energizing each block, for reducing a maximum attainable temperature of the thermal head and, moreover, for thermal ink transfer, are divided into a plurality of times for recording.
However, as in the example of the aforementioned prior art, the recording method of energizing each block a plurality of times for recording, has less energy applied to the thermal head as compared with the recording method of energizing each block only once. This has led to the problem that the time required for recording each line becomes longer in order to record one line with sufficient density secured. Also, if a time interval for each line changes, uneven image density may occur.